Ship construction



y 2 1960 v. AllBlACH 2,937,607

' SHIP CONSTRUCTION Filed April 27. 1954 4 Sheets-Sheet 1 I Jig 3 2e 25 22 INVENTOR Va'menfAIazcfi ATTORNEY$ May 24, 1960 v. ALBIACH 50 sax? CONSTRUCTION Filed April 27, 1954 4 Sheets-Sheet 2 26 40 wmnmlaza ATTORNEYS May 24, 1960 Filed April 27, 1954 V. ALBIACH SHIP CONSTRUCTION 4 Sheets-Sheet 3 I INVENTOR Vvzcenf/Uhacb ATTORNEYS y 1960 v. ALBIACH 2,937,607

SHIP CONSTRUCTION 4 Sheets-Sheet 4 Filed April 27, 1954 I n 'IIIIIIIIIII IIIflI/IIIIIIIIIII; 'IIIIIIAIIIII INVENTOR ATTORNEYS United States Patent SHIP CONSTRUCTION Vincent Albiach, 76 Rue Spontini, Paris 16, France Filed Apr. 27, 1954, Ser. No. 425,928

12 Claims. (Cl. 114-79) This invention relates to ship construction and particularly to a tanker, of the longitudinally framed type having an improved arrangement for interconnecting the longitudinals at their intersections with the transverse bulkheads.

Among all the types of merchant ships, those vessels intended for the transportation of petroleum or other liquids in bulk are particularly aflfected by conditions at sea, due to their reduced superstructure, the aft location of the propelling installation, and the nature of the cargo. Years of research and experience in the construction and operation of tankers has led to a design now classical, wherein the modern tanker is built with two side longitudinal bulkheads, and is of the longitudinally framed type in accordance with the Isherwood system. It is generally agreed, and reason and experience show it to be well founded, that from the point of view of the deck and bottom structure, the usual arrangement of spaced bottom and deck transverses which constitute the primary stiifening and longitudinal frames which constitute the secondary stiffening is the most reasonable and most economical type of construction.

A diflicult problem however arises concerning the intersection of the longitudinal members with the transverse bulkheads. It is necessary that the longitudinals, which by their arrangement contribute to the general strength of the ship girder, possess suitable continuity while at the same time allow some flexibility at this position in order to avoid any concentration of stress in the bulkhead bottom or deck plating, also in the longitu dinal itself at its connection with the connecting member.

In my copending application Serial No. 243,464, filed August 24, 1951, now abandoned of which this application is a continuation-in-part, I have disclosed an improved arrangement for connecting the longitudinals of a ship in the region of a transverse bulkhead, so as to avoid the overstresses experienced in prior art arrangements for coupling the longitudinals on each side of the bulkhead. In the preferred arrangement of my prior application, the bulkhead has an opening aligned with the longitudinal sections formed by the interruption of the longitudinal by the bulkhead, and an arcuate or polygonal coupling element extends through this bulkhead opening so as to penetrate into complementary recesses provided in the web portions of these longitudinals, to which the coupling element is fastened by welding.

The present invention has for its principal object the provision of certain improvements of my aforementioned arrangement. These improved arrangements are characterized primarily by providing the coupling element with a cross-sectional area at least as great as that of the longitudinal member, and disposing its center of gravity at about the same height as that of the longitudinal members, and about in the same longitudinal plane as that of the centers of gravity of the unaltered sections of longitudinals, with the result that both lateral and vertical eccentricity between the coupling element 2 and the longitudinal sections are avoided. With this arrangement, superimposing of the general stresses to which the hull is subjected under hogging and sagging, and the local stresses due to the static and dynamic pressures of the liquid cargo or seawater, is avoided to the greatest possible extent.

The present invention also has reference to improvements in the manner ofconnecting the coupling element to the longitudinal sections, an arrangement providing reinforcement and homogeneity of strain in the bottom or deck plating adjacent the longitudinal sections, and other features which will be described with reference to the accompanying drawings.

In the drawings: I

Fig. 1 is a longitudinal sectional view of part of a ship hull, showing one embodiment of the structure of the present invention;

Figs. 2 and 3 are transverse sectional (on line 22 of Fig. '1) and plan views, respectively, of the structure;

Figs. 4, 5 and 6 are view similar to Figs. 1, 2 and 3,

respectively, but showing a modified form of the struc' ture;

Fig. 7 is a plan view of part of a further modification, showing slippings associated with the longitudinal sec tions near the transverse bulkhead;

Figs. 8, 9 and 10 are views similar to Figs.-1, 2 and 3, respectively, but showing another embodiment;

Figs. 11 and 12 are sectional views of alternating dc tails of the structure shown in Figs. 8-10;

Figs. 13, 14 and 15 are transverse sectional, longitudinal sectional and plan views, respectively, of a further embodiment;

Figs. 16 is a longitudinal sectional view of another form of the invention as applied to existing ship structures;

Fig. 17 is a sectional view on line 17-17 in Fig. 16, and

Fig. 18 is a longitudinal sectional view of a modification of the structures in the preceding illustrations.

Referring now to Figs. 1-3, the bottom plating of the ship hull is shown at 20, and one of the longitudinal frames associated with this bottom plating is shown at 21. At the region of a transverse bulkhead 22, the longitudinal member 21 is interrupted to form end portions 23. As best shown in Fig.1, each 'end portion 23 of a longitudinal section is provided at the top with a bulb or flange 24, so that it is generally T-shaped in cross section; and this top flange 24 slants downward toward bulkhead 22 to the point where the longitudinal section is stopped short of the bulkhead. A coupling element 25 extends through an opening 22a in the bulkhead, this opening being aligned with the interrupted longitudinal member 21. As shown in Fig. 1, the coupling element 25 is in the shape of a trapezoid so that its fits into the recess formed by the lowered end portions 23 of the longitudinal member. The coupling element 25 may be secured to these end portions 23 in any suitable manner, as by welding or by providing it with bottom flanges 26 secured to the flanges 24 by rivets 27. A flange plate 28 may be welded to the bulkhead and to the coupling element 25 which passes through this flange plate.

The coupling element 25 is at such a height that the center of gravity, in way of the transverse bulkhead, of the section consisting of this coupling element and the associated bottom plating 20 is at approximately the same height as the center of gravity of the longitudinal member 21 (at its unaltered portion of normal height) and the associated bottom plating. By reason of this, and the alignment of the coupling element 25 with the interruptedlongitudinal member 21, any lateral or vertical eccentric;

ity between the coupling member element and the lon itudinal is avoided.

As shown in Fig. 1, each end portion 23 of a longitudinal section is provided with a separation line 29 spaced somewhat below the slanting top flange or bulb 24 and parallel thereto. If the longitudinals are of a built up type in which the web and flange are welded together, the slanted form of the end portions is obtained by a proper flame cutting of the Web, before welding the flange. If, on the contrary, the longitudinals are of a solid section type as a rolled bulb plate or T shaped form, each end portion is provided with a separation line 29 spaced somewhat below the slanting top flange or bulb 24. To provide this downward slant of, the end portions, 2. generally triangular section 30 is cut from each unaltered end portion of the longitudinal member 21 at the region where it is interrupted by the transverse bulkhead 22, as by cutting the vertical web of the longitudinal member along the dotted line 31 and the full line 29 in Fig. l (where the unaltered end portion is also shown in dotted lines). The line 29 effects a curved form at the extremity of the recess in the web so that the upper part of the end portion of the longitudinal may be forced down to close the gap left by removal of the triangular section 30, thereby'forming a separation line 29. The provision of the curved form at the extremity of this line allows a progressive elongation of the upper part of the longitudinals in this region. Ifsuch a curved line were not provided, the upper part would be overstressed at the extremity of the triangular section 30, when the end portion is forced down to'close the gap.

A proper welding must be provided along the line 29 so as to complete the strength of the structure. Stitfeners 32 may be provided to join the top flanges 24 at the end portion 23 to the bottom or deck plating, and also to avoid the lateral buckling of the web longitudinals under compression.

In the arrangement shown in Figs. 4, and 6, the coupling element 25a is shown in the form of a heavy solid bar of polygonal cross section or a thick horizontal gusset plate, although it may be, of rounded or other section. The end portions 23a of the longitudinal member are stopped at a certain distance from the bulkhead 22, preferably in an oblique section. The top flange 24a of the longitudinal member is bent downward to the bottom plating 20, at the end portions 23a, at opposite sides of the bulkhead. This downward slanting of the longitudinal sections can be accomplished by removing triangular sections and forcing the flange 24a downward, as previously described, forming the separation lines Zi a. Brackets 34 of suitable section are fitted above and below the connecting element 25a and are welded to the latter as well as to the flange 24a of the end portions of the longitudinal member.

To avoid stress concentrations at the end portions of the longitudinal member adjacent the transverse bulkhead 22, slippings can be added to the latter so as to distribute the stresses transmitted by the longitudinal member. Such an arrangement is illustrated in Fig. 7. As there shown, slippings 36 are welded to each side of the longitudinal member 2111 at the region where it is interrupted by the bulkhead 22, and these slippings in turn are welded or riveted to the bottom plating 20.

Referring now to Figs. 8-12, the coupling element 250 is formed by a thick plate of trapezoidal or other shape welded to the bottom plating 20 and connected to the vertical web of each longitudinal end portion 23c, by means of checks 38. A cheek 38 is provided at each side of each longitudinal end portion 230 and is welded in substantially end-to-end abutting relation to the coupling element 250. Also, each check 38 is riveted to the web of the corresponding longitudinal end portion 23c.

Special care should be taken to obtain an efficient welding between the cheeks 38 and the coupling element 25, on account of the fact that this welding will normally be made, at least partly, on the spot, so that the back-run of the welding is not possible. As shown in Fig. 11, each cheek 38 forms with the abutting coupling element 250 a notch 39, as by providing the coupling element or the cheeks, or both, with a beveled edge. The notch 39 receives the welding 40 and issubstantially closed at the bottom. As shown in Fig. 12, the coupling element 25c forms a small lug under the beveled edge of the cheek 38, so that the welding may go to the bottom of this beveled edge without leakage of fused metal. If desired, this lug underlying the beveled edge of the cheek may be formed by a bar 41 locked in a recess in the coupling element, as shown in Fig. 12.

The aforesaid description of Figs. 8-9 and 10 applies to a riveted connection but, of course, an entirely welded connection may be obtained with this design in suppressing the cheeks 38; then, the connecting element 25c should be butt-welded to the web and flange of the longitudinals so as to insure the required continuity.

In Figs. 13-15, the longitudinal members 21 are supplemented by intermediate auxiliary longitudinal members 43 made of thick plate or solid sections but of smaller height than the main longitudinals 21. The members 43 are stopped short of the transverse bulkhead 22; but their continuity can be assured by connecting their adjacent ends through the bulkhead by means of coupling elements as previously described with reference to the longitudinal members of the previous embodiments. As shown in Figs. 13-15, however, the auxiliary longitudinals 43 are reinforced and completed by transverse members 44 connected to and supported by the main longitudinals 21 at both sides of the auxiliary longitudinals. This provides a better distribution of the stresses in the bottom plating 20 in the vicinity of the bulkhead.

In Figs. 16 and 17, I have shown an example of the application of the invention to an existing ship structure, in which the longitudinal 21 has a flanged top 46 and is joined at its end portions 23 by a thick bracket 47 passing through the transverse bulkhead 22 and welded to the top flange 46. According to the invention, the longitudinal 21 is first reinforced by a thick plate or solid section 48 fixed to each longitudinal section along its entire length, as by welding or riveting. To reinforce the connection at the bulkhead and lower the center of gravity of the coupling and bottom plating assembly, the longitudinal end portions 23 are connected by a coupling element 49 riveted or welded thereto and either recessed in the webs 21 or lapped thereon, as shown in Figs. 16 and 17. This coupling element extends through the bulkhead and is also riveted or welded to the reinforcing elements 48. In this way, the center of gravity of the assembly is lowered to conform to the condition described in connection with Figs. 1-3, which applies also to the other forms. It will be observed from Fig. 16 that the original triangular shape of the brackets 47 in the existing ship structure has been altered by cutting along a curved line so a to reduce the transverse section of these brackets and increase their flexibility under the bending moment applied to the longitudinal by the local forces due to the pressure of the liquid cargo. This alteration is compensated by the addition of the new connecting member 49 placed at a lower height and connected to the additional reinforcing bars 48. Thus, the center of gravity of the modified structure, while not corresponding exactly to that of the other embodiments of the invention, conforms closely thereto.

In Figs. 18-19-20 and 21, I have shown an end portion 54) of a deck or bottom longitudinal, where it is interrupted by the transverse bulkhead 22, this longitudinal being associated with deck or bottom plating 51. A coupling element 52 of circular or polygonal cross section has one end tapered downward and recessed in the web of the longitudinal end portion 50, to which it is welded. This coupling element extends through an aligned opening in the bulkhead 22 and has its other end similarly tapered and secured to the adjacent longitudinal end portion (not shown) at the opposite side of the bulkhead.

The triangular recess provided into the web is extended, as per a flame-cut line 54, in the deck or bottom longitudinals so as to facilitate the fairing of the upper part of the longitudinal with the connecting element. The welding of the connecting element to the web is extended, as per line 54, so as to reestablish the proper strength of the structure. As an alternative, the lower part of the end portion may be constituted by a separate plate as per dotted line 55 so as to ease the erection and the fairing. A proper welding is provided along the said dotted line so as to re-establish the proper strength of the structure.

:One or two collars are provided to facilitate the fairing and to provide a proper oil tightness of the bulkhead. Stitfeners 56 may be added to reinforce the structure and to avoid the lateral buckling of the web longitudinals.

It will be understood that the cross-sectional area and center of gravity of the coupling element 52 comply with the conditions previously described.

It will be also understood that all the structures previously described are applicable to deck longitudinals as well as to the longitudinals associated with the bottom or side plating of longitudinally framed ships.

I claim:

1. In a ship construction having a longitudinal frame member and having a transverse bulkhead interrupting the longitudinal member and dividing it into longitudinal sections, the improvement which comprises a continuous coupling element extending through the bulkhead between adjacent end portions of the longitudinal sections at opposite sides of the bulkhead, said longitudinal sections terminating short of the bulkhead, the coupling element having a cross-sectional area at least as great as that of the longitudinal frame member and having its center of gravity at about the same height and about in the same longitudinal plane as that of the centers of gravity of the unaltered sections of the aligned longitudinal members, the bulkhead having an opening aligned with said sections and through which the coupling element extends loosely, and means securing each end portion of the coupling element to the adjacent longitudinal section.

2. The improvement according to claim 1, in which the end portions of the longitudinal sections adjacent the bulkhead are lower than the main portions of said sections, the coupling element being secured to said lowered end portions of said sections.

3. The improvement according to claim 1, in which the end portions of the longitudinal sections are recessed to receive the end portions of the coupling element.

4. The improvement according to claim 1, in which the end portions of the longitudinal sections are recessed to receive the end portions of the coupling element, said securing means including cheeks riveted to the longitudinal sections and welded to the end portions of the coupling element.

5. The improvement according to claim 1, in which said securing means including cheeks riveted to the longitudinal sections and welded to the end portions of the coupling element, each cheek being in substantially endto-end abutting relation with the coupling element and forming therewith a notch substantially closed at the bottom for receiving the welding.

6. The improvement according to claim 1, in which said securing means include cheeks riveted to the longitudinal sections and welded to the end portions of the coupling element, each cheek being in substantially endto-end abutting relation with the coupling element and forming therewith a notch for receiving the welding, and a bar located between said cheek and coupling element and positioned at the bottom of the notch to retain the welding therein.

7. The improvement according to claim 1, in which said securing means include a bracket connected to each end portion of the coupling element and the adjacent longitudinal section, and comprising also bottom plating connected to the brackets.

8. The improvement according to claim 1, in which said securing means include a bracket connected to each end portion of the coupling element and the adjacent longitudinal members, said auxiliary members providing the coupling element.

9. The improvement according to claim 1, comprising also auxiliary longitudinal members in spaced relation to the first longitudinal member but of smaller height than said first member, and horizontal plating adjacent said longitudinal members, said auxiliary member providing reinforcement and homogeneity of strain in said plating.

10. The improvement according to claim 1, comprising also auxiliary longitudinal members in spaced relation to the first longitudinal member but of smaller height than said first member, and horizontal plating adjacent said longitudinal members, said auxiliary members providing reinforcement and homogeneity of strain in said plating, and a transverse reinforcing member connected between said first longitudinal member and each auxiliary member.

11. The improvement according to claim 1, in which the end portions of the longitudinal sections adjacent the bulkhead are slanted downward toward the bulkhead, the coupling element being secured to said slanted end portions, said last end portions each having a slanted and/or curved separation line formed by removing a generally triangular section from the end portion and forcing the upper part of said end portion downward to close the gap left by said removal.

12. The improvement according to claim 1, in which the end portions of the longitudinals are provided with a recess complementary of end portions of the connecting element fastened by welding, the end of said recess being extended into the web longitudinal as per a flame cut curved or straight line.

References Cited in the file of this patent UNITED STATES PATENTS 1,837,078 Smith Dec. 15, 1931 2,053,903 Frear Sept. 8, 1936 2,053,904 Frear Sept. 8, 1936 2,254,561 Benthem Sept. 2, 1941 FOREIGN PATENTS 349,870 Great Britain June 4, 1931 381,293 Great Britain Oct. 6, 1932 828,847 France Feb. 28.. 1938 

